The well-known equations for the powder compaction process (PCP) in a rigid die published from the beginning of the last century until today were considered in this review. Most of the considered equations are converted into the dependences of densification pressure on the powder’s relative density. The equations were analyzed and their ability to describe PCP was assessed by defining the coefficient of determination when approximating experimental data on the compaction of various powders. It was shown that most of the equations contain two constants the values of which are determined by fitting the mathematical dependence to the experimental curve. Such equations are able to describe PCP with high accuracy for the compaction of powders up to a relative density of 0.9–0.95. It was also shown that different equations can describe PCP in the density range from the initial density to 0.9 with the same high accuracy, but when the process of compaction is extrapolated to higher values of density, the curves diverge. This indicates the importance of equations that can unambiguously describe PCP to a relative density equal to or close to 1.0. For an adequate description of PCP for relative density greater than 0.95, equations containing three or four constants have proven useful.
{"title":"New Die-Compaction Equations for Powders as a Result of Known Equations Correction: Part 1–Review and Analysis of Various Die-Compaction Equations","authors":"Anatolii V. Laptiev","doi":"10.3390/powders3010008","DOIUrl":"https://doi.org/10.3390/powders3010008","url":null,"abstract":"The well-known equations for the powder compaction process (PCP) in a rigid die published from the beginning of the last century until today were considered in this review. Most of the considered equations are converted into the dependences of densification pressure on the powder’s relative density. The equations were analyzed and their ability to describe PCP was assessed by defining the coefficient of determination when approximating experimental data on the compaction of various powders. It was shown that most of the equations contain two constants the values of which are determined by fitting the mathematical dependence to the experimental curve. Such equations are able to describe PCP with high accuracy for the compaction of powders up to a relative density of 0.9–0.95. It was also shown that different equations can describe PCP in the density range from the initial density to 0.9 with the same high accuracy, but when the process of compaction is extrapolated to higher values of density, the curves diverge. This indicates the importance of equations that can unambiguously describe PCP to a relative density equal to or close to 1.0. For an adequate description of PCP for relative density greater than 0.95, equations containing three or four constants have proven useful.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"48 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140234373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Particle aggregation is essential in many industrial processes, spanning the pharmaceutical and food industries, polymer production, and the environment, among others. However, aggregation can also occur, in some processes, as a non-desired side effect. Thus, to be able to monitor aggregation in industrial processes is of high importance to guarantee that the final, required product characteristics are obtained. In this paper, we present an extensive review of the different techniques available for monitoring particle characteristics in industrial processes involving particulate materials, with special emphasis on aggregation processes. These methods include both off-line and on-line techniques, based either on image acquisition techniques or different radiation scattering techniques (light-scattering and ultrasound spectroscopy). The principles behind each technique are addressed, together with their relevant applications, advantages, and disadvantages.
{"title":"Monitoring Aggregation Processes in Multiphase Systems: A Review","authors":"M. Rasteiro, Antti Koponen","doi":"10.3390/powders3010007","DOIUrl":"https://doi.org/10.3390/powders3010007","url":null,"abstract":"Particle aggregation is essential in many industrial processes, spanning the pharmaceutical and food industries, polymer production, and the environment, among others. However, aggregation can also occur, in some processes, as a non-desired side effect. Thus, to be able to monitor aggregation in industrial processes is of high importance to guarantee that the final, required product characteristics are obtained. In this paper, we present an extensive review of the different techniques available for monitoring particle characteristics in industrial processes involving particulate materials, with special emphasis on aggregation processes. These methods include both off-line and on-line techniques, based either on image acquisition techniques or different radiation scattering techniques (light-scattering and ultrasound spectroscopy). The principles behind each technique are addressed, together with their relevant applications, advantages, and disadvantages.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"20 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140243791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The flowability of food powders is a critical determinant of their processing efficiency, product quality, and overall operational success. This review delves into the intricacies of powder flowability, elucidating the factors that govern it and exploring various methods for its evaluation and enhancement. Particle size and distribution, particle shape, surface properties, moisture content, and storage conditions stand as the key determinants of powder flowability. Finer powders, with their increased interparticle cohesive forces, tend to exhibit poorer flowability. Particle shape also plays a role, with irregular or elongated particles flowing less readily than spherical ones. Surface properties influence interparticle friction, thereby impacting flow behavior. Moisture content significantly affects flowability, as increased moisture can lead to liquid bridge formation, hindering powder movement. Storage temperature, on the other hand, generally enhances powder flow due to reduced interparticle cohesive forces at higher temperatures. This highlights the need to understand the factors influencing food powder flowability and to employ appropriate evaluation strategies for optimizing food powder processing efficiency, product quality, and overall production success.
{"title":"Factors Influencing Food Powder Flowability","authors":"R. Suhag, Abdessamie Kellil, Mutasem Razem","doi":"10.3390/powders3010006","DOIUrl":"https://doi.org/10.3390/powders3010006","url":null,"abstract":"The flowability of food powders is a critical determinant of their processing efficiency, product quality, and overall operational success. This review delves into the intricacies of powder flowability, elucidating the factors that govern it and exploring various methods for its evaluation and enhancement. Particle size and distribution, particle shape, surface properties, moisture content, and storage conditions stand as the key determinants of powder flowability. Finer powders, with their increased interparticle cohesive forces, tend to exhibit poorer flowability. Particle shape also plays a role, with irregular or elongated particles flowing less readily than spherical ones. Surface properties influence interparticle friction, thereby impacting flow behavior. Moisture content significantly affects flowability, as increased moisture can lead to liquid bridge formation, hindering powder movement. Storage temperature, on the other hand, generally enhances powder flow due to reduced interparticle cohesive forces at higher temperatures. This highlights the need to understand the factors influencing food powder flowability and to employ appropriate evaluation strategies for optimizing food powder processing efficiency, product quality, and overall production success.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"79 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140421233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Giesler, L. Weirauch, Jorg Thöming, G. Pesch, M. Baune
The development of highly selective separation processes is a focus of current research. In 2016, the German Science Foundation funded a priority program SPP 2045 “MehrDimPart—highly specific multidimensional fractionation of fine particles with technical relevance” that aims to develop new or enhance existing approaches for the separation of nano- and micrometer-sized particles. Dielectrophoretic separators achieve highly selective separations of (bio-)particles in microfluidic devices or can handle large quantities when non-selective separation is sufficient. Recently, separator designs were developed that aim to combine a high throughput and high selectivity. Here, we summarize the development from a microfluidic fast chromatographic separation via frequency modulated dielectrophoretic particle chromatography (DPC) toward a macrofluidic high throughput separation. Further, we provide a starting point for future work by providing new experimental data demonstrating for the first time the trapping of 200 nm polystyrene particles in a dielectrophoretic high-throughput separator that uses printed circuit boards as alternatives for expensive electrode arrays.
{"title":"Dielectrophoretic Particle Chromatography: From Batch Processing to Semi-Continuous High-Throughput Separation","authors":"J. Giesler, L. Weirauch, Jorg Thöming, G. Pesch, M. Baune","doi":"10.3390/powders3010005","DOIUrl":"https://doi.org/10.3390/powders3010005","url":null,"abstract":"The development of highly selective separation processes is a focus of current research. In 2016, the German Science Foundation funded a priority program SPP 2045 “MehrDimPart—highly specific multidimensional fractionation of fine particles with technical relevance” that aims to develop new or enhance existing approaches for the separation of nano- and micrometer-sized particles. Dielectrophoretic separators achieve highly selective separations of (bio-)particles in microfluidic devices or can handle large quantities when non-selective separation is sufficient. Recently, separator designs were developed that aim to combine a high throughput and high selectivity. Here, we summarize the development from a microfluidic fast chromatographic separation via frequency modulated dielectrophoretic particle chromatography (DPC) toward a macrofluidic high throughput separation. Further, we provide a starting point for future work by providing new experimental data demonstrating for the first time the trapping of 200 nm polystyrene particles in a dielectrophoretic high-throughput separator that uses printed circuit boards as alternatives for expensive electrode arrays.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"29 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139862480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Giesler, L. Weirauch, Jorg Thöming, G. Pesch, M. Baune
The development of highly selective separation processes is a focus of current research. In 2016, the German Science Foundation funded a priority program SPP 2045 “MehrDimPart—highly specific multidimensional fractionation of fine particles with technical relevance” that aims to develop new or enhance existing approaches for the separation of nano- and micrometer-sized particles. Dielectrophoretic separators achieve highly selective separations of (bio-)particles in microfluidic devices or can handle large quantities when non-selective separation is sufficient. Recently, separator designs were developed that aim to combine a high throughput and high selectivity. Here, we summarize the development from a microfluidic fast chromatographic separation via frequency modulated dielectrophoretic particle chromatography (DPC) toward a macrofluidic high throughput separation. Further, we provide a starting point for future work by providing new experimental data demonstrating for the first time the trapping of 200 nm polystyrene particles in a dielectrophoretic high-throughput separator that uses printed circuit boards as alternatives for expensive electrode arrays.
{"title":"Dielectrophoretic Particle Chromatography: From Batch Processing to Semi-Continuous High-Throughput Separation","authors":"J. Giesler, L. Weirauch, Jorg Thöming, G. Pesch, M. Baune","doi":"10.3390/powders3010005","DOIUrl":"https://doi.org/10.3390/powders3010005","url":null,"abstract":"The development of highly selective separation processes is a focus of current research. In 2016, the German Science Foundation funded a priority program SPP 2045 “MehrDimPart—highly specific multidimensional fractionation of fine particles with technical relevance” that aims to develop new or enhance existing approaches for the separation of nano- and micrometer-sized particles. Dielectrophoretic separators achieve highly selective separations of (bio-)particles in microfluidic devices or can handle large quantities when non-selective separation is sufficient. Recently, separator designs were developed that aim to combine a high throughput and high selectivity. Here, we summarize the development from a microfluidic fast chromatographic separation via frequency modulated dielectrophoretic particle chromatography (DPC) toward a macrofluidic high throughput separation. Further, we provide a starting point for future work by providing new experimental data demonstrating for the first time the trapping of 200 nm polystyrene particles in a dielectrophoretic high-throughput separator that uses printed circuit boards as alternatives for expensive electrode arrays.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"59 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139802432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
From the first principles simulation (using the method of “a priori pseudopotential” and the “quasi-harmonic approximation” method- author’s developments), the basic characteristics of diborides and diborides of multielement transition metals (DMTMs) with an AlB2 type structure were calculated. For both diborides and DMTMs, the linear coefficients of thermal expansion (LCTE) along the axial axes differ little from each other, i.e., transition metal diborides and hexagonal lattice DMTMs are quasi-isotropic. Quasi-isotropy makes it possible to estimate the LCTE using an analytical formula that depends on the melting temperature. In the absence of experimental data on the melting point of DMTMs, a method for calculating it from first principles is presented. The theoretical hardness values of transition metal diborides and DMTMs with averaged parameters were calculated from the first principles. The hardness of both bulk and nano-sized DMTMs was assessed using a hybrid method. There is agreement between the calculated and available experimental data.
{"title":"Diborides of Multielement Transition Metals: Methods for Calculating Physical and Mechanical Characteristics","authors":"D. Zakarian, Aik Khachatrian, Sergey Firstov","doi":"10.3390/powders3010004","DOIUrl":"https://doi.org/10.3390/powders3010004","url":null,"abstract":"From the first principles simulation (using the method of “a priori pseudopotential” and the “quasi-harmonic approximation” method- author’s developments), the basic characteristics of diborides and diborides of multielement transition metals (DMTMs) with an AlB2 type structure were calculated. For both diborides and DMTMs, the linear coefficients of thermal expansion (LCTE) along the axial axes differ little from each other, i.e., transition metal diborides and hexagonal lattice DMTMs are quasi-isotropic. Quasi-isotropy makes it possible to estimate the LCTE using an analytical formula that depends on the melting temperature. In the absence of experimental data on the melting point of DMTMs, a method for calculating it from first principles is presented. The theoretical hardness values of transition metal diborides and DMTMs with averaged parameters were calculated from the first principles. The hardness of both bulk and nano-sized DMTMs was assessed using a hybrid method. There is agreement between the calculated and available experimental data.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"10 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139595898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The low deposition efficiency in directed energy deposition (DED) has prompted the reuse of powders that do not fuse to the builds to make additive manufacturing more sustainable. It is unknown, however, how the properties of the powder and deposited parts change as powders are continuously reused. In this study, AlSi10Mg was investigated for five deposition cycles in DED. Exposing AlSi10Mg powder to DED conditions changes the morphology, size, and flowability. The mechanical properties of AlSi10Mg DED parts decreased after the feedstock powder was reused one time. Notably, no additional significant changes were observed when the powder was further reused.
{"title":"The Reusability of AlSi10Mg Powder in Directed Energy Deposition","authors":"P. Kiani, A. Dupuy, Kaka Ma, J. Schoenung","doi":"10.3390/powders3010003","DOIUrl":"https://doi.org/10.3390/powders3010003","url":null,"abstract":"The low deposition efficiency in directed energy deposition (DED) has prompted the reuse of powders that do not fuse to the builds to make additive manufacturing more sustainable. It is unknown, however, how the properties of the powder and deposited parts change as powders are continuously reused. In this study, AlSi10Mg was investigated for five deposition cycles in DED. Exposing AlSi10Mg powder to DED conditions changes the morphology, size, and flowability. The mechanical properties of AlSi10Mg DED parts decreased after the feedstock powder was reused one time. Notably, no additional significant changes were observed when the powder was further reused.","PeriodicalId":507225,"journal":{"name":"Powders","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139625497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Boron carbide (B4C) powders with defined stoichiometry, high crystallinity, minimal impurity content, and a fine particle size are imperative for realizing the exceptional properties of this compound in advanced high-technology applications. Nevertheless, achieving the desired stoichiometry and particle size using traditional synthesis methods, which rely on prolonged high-temperature processes, can be challenging. The primary objective of this study is to synthesize fine B4C powders characterized by high crystallinity and a sub-micron particle size, employing a fast and energy-efficient method. B4C powders are synthesized from elemental boron and carbon in a high-frequency induction heating furnace using the electromagnetic induction synthesis (EMIS) method. The rapid heating rate achieved through contactless heating promotes the ignition and propagation of the exothermic chemical reaction between boron and carbon. Additionally, electromagnetic effects accelerate atomic diffusion, allowing the reaction to be completed in an exceptionally short timeframe. The grain size and crystallinity of B4C can be finely tuned by adjusting various process parameters, including the post-ignition holding temperature and the duration of heating. As a result, fine B4C powders can be synthesized in under 10 min. Moreover, these synthesized B4C powders exhibit oxidation onset temperatures higher than 500 °C when exposed to air.
{"title":"Fast Synthesis of Fine Boron Carbide Powders Using Electromagnetic Induction Synthesis Method","authors":"A. Gubarevich, Katsumi Yoshida","doi":"10.3390/powders3010002","DOIUrl":"https://doi.org/10.3390/powders3010002","url":null,"abstract":"Boron carbide (B4C) powders with defined stoichiometry, high crystallinity, minimal impurity content, and a fine particle size are imperative for realizing the exceptional properties of this compound in advanced high-technology applications. Nevertheless, achieving the desired stoichiometry and particle size using traditional synthesis methods, which rely on prolonged high-temperature processes, can be challenging. The primary objective of this study is to synthesize fine B4C powders characterized by high crystallinity and a sub-micron particle size, employing a fast and energy-efficient method. B4C powders are synthesized from elemental boron and carbon in a high-frequency induction heating furnace using the electromagnetic induction synthesis (EMIS) method. The rapid heating rate achieved through contactless heating promotes the ignition and propagation of the exothermic chemical reaction between boron and carbon. Additionally, electromagnetic effects accelerate atomic diffusion, allowing the reaction to be completed in an exceptionally short timeframe. The grain size and crystallinity of B4C can be finely tuned by adjusting various process parameters, including the post-ignition holding temperature and the duration of heating. As a result, fine B4C powders can be synthesized in under 10 min. Moreover, these synthesized B4C powders exhibit oxidation onset temperatures higher than 500 °C when exposed to air.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"6 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139445985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. H. Lew, P. Luckham, O. K. Matar, Erich A. Müller, Adrielle Sousa Santos, Myo Thant Maung Maung
In this work, the consolidation of calcium carbonate (CaCO3) by polyacrylamide (PAM) of different molecular weights, charge densities, and functional groups was investigated via oscillatory rheology and unconfined compressive strength (UCS) analysis. Oscillatory rheology showed that the storage modulus G′ was approximately 10 times higher than the loss modulus G″, indicating a highly elastic CaCO3 sample upon consolidation via PAM. Both oscillatory rheology and UCS analysis exhibited similar trends, wherein the mechanical values (G′, G″, and UCS) first increased with increasing polymer dosage, until they reached a peak value (typically at 3 mgpol/gCaCO3), followed by a decrease in the mechanical values. This indicates that there is an optimum polymer dosage for the different PAM-CaCO3 colloidal systems, and that exceeding this value induces the re-stabilisation of the colloidal system, leading to a decreased degree of consolidation. Regarding the effect of the PAM molecular weight, the peak G’ and UCS values of CaCO3 consolidated by hydrolysed PAM (HPAM) of different molecular weights are very similar. This is likely due to the contour length of the HPAMs being either almost the same or longer than the average distance between two CaCO3 particles. The effect of the PAM charge density revealed that the peak G′ and UCS values decreased as the charge density of the PAM increased, while the optimum PAM dosage increased with decreasing PAM charge density. The higher likelihood of lower-charge PAM bridging between the particles contributes to higher elastic energy and mechanical strength. Finally, regarding the PAM functional group, CaCO3 consolidated by sulfonated polyacrylamide (SPAM) typically offers lower mechanical strength than that consolidated with HPAM. The bulky sulfonate side groups of SPAM interfere with the surface packing, reducing the number of polymers able to adsorb onto the surface and, eventually, reducing the degree of consolidation of CaCO3. The zeta potential of the PAM-CaCO3 samples became more negative with increasing PAM concentration due to the saturation of the particle surface. Good agreement between oscillatory rheology and UCS analysis could accelerate PAM screening for optimum CaCO3 consolidation.
{"title":"Consolidation of Calcium Carbonate Using Polyacrylamides with Different Chemistries","authors":"J. H. Lew, P. Luckham, O. K. Matar, Erich A. Müller, Adrielle Sousa Santos, Myo Thant Maung Maung","doi":"10.3390/powders3010001","DOIUrl":"https://doi.org/10.3390/powders3010001","url":null,"abstract":"In this work, the consolidation of calcium carbonate (CaCO3) by polyacrylamide (PAM) of different molecular weights, charge densities, and functional groups was investigated via oscillatory rheology and unconfined compressive strength (UCS) analysis. Oscillatory rheology showed that the storage modulus G′ was approximately 10 times higher than the loss modulus G″, indicating a highly elastic CaCO3 sample upon consolidation via PAM. Both oscillatory rheology and UCS analysis exhibited similar trends, wherein the mechanical values (G′, G″, and UCS) first increased with increasing polymer dosage, until they reached a peak value (typically at 3 mgpol/gCaCO3), followed by a decrease in the mechanical values. This indicates that there is an optimum polymer dosage for the different PAM-CaCO3 colloidal systems, and that exceeding this value induces the re-stabilisation of the colloidal system, leading to a decreased degree of consolidation. Regarding the effect of the PAM molecular weight, the peak G’ and UCS values of CaCO3 consolidated by hydrolysed PAM (HPAM) of different molecular weights are very similar. This is likely due to the contour length of the HPAMs being either almost the same or longer than the average distance between two CaCO3 particles. The effect of the PAM charge density revealed that the peak G′ and UCS values decreased as the charge density of the PAM increased, while the optimum PAM dosage increased with decreasing PAM charge density. The higher likelihood of lower-charge PAM bridging between the particles contributes to higher elastic energy and mechanical strength. Finally, regarding the PAM functional group, CaCO3 consolidated by sulfonated polyacrylamide (SPAM) typically offers lower mechanical strength than that consolidated with HPAM. The bulky sulfonate side groups of SPAM interfere with the surface packing, reducing the number of polymers able to adsorb onto the surface and, eventually, reducing the degree of consolidation of CaCO3. The zeta potential of the PAM-CaCO3 samples became more negative with increasing PAM concentration due to the saturation of the particle surface. Good agreement between oscillatory rheology and UCS analysis could accelerate PAM screening for optimum CaCO3 consolidation.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"35 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139166800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Modeling powder properties remains a complex and difficult area of study because particulate materials can behave differently under variable conditions based on their bulk and surface-level properties. The research presented in this manuscript was designed to support the fundamental understanding of powder systems by joining experimental and theoretical calculations of dimensionless numbers groups for design purposes. In order to do so, this work focused on two critical variables to better understand fluidization design: physical and chemical surface properties. To better resolve the influence of surface properties, surface-treated powders were used. Five different powder samples of varying particle size distribution were characterized using physical property measurements, including pressure drop profiles to obtain the minimum fluidization velocity, density measurements, and particle sizing. Using theoretical equations, the minimum fluidization velocity was also calculated to compare with those obtained experimentally and determine typical dimensionless number groups used in bulk handling system design. The results showed that the theoretically determined values were lower than those calculated using the experimentally umf. In the case of the Reynolds number, the experimental values were 3–20% higher than the theoretical values, which is an important distinction for designing conveying systems and pipeline flow. Similar results were observed for the theoretical and experimental Froude numbers, indicating an important dependence on the cohesive properties of the particle interactions. Additional dimensionless number groups were considered, including the granular bond number and flow factors. To investigate the influence of surface forces, Hamaker constants were utilized for alumina and polydimethylsiloxane in the calculation of the granular bond number. A lower granular bond was observed with a decrease in the Hamaker constant for PDMS, suggesting that the surface forces would be lower for our surface-treated powders.
{"title":"Dimensionless Number Group Analysis of Surface-Treated Powders","authors":"B. Ludwig","doi":"10.3390/powders2040047","DOIUrl":"https://doi.org/10.3390/powders2040047","url":null,"abstract":"Modeling powder properties remains a complex and difficult area of study because particulate materials can behave differently under variable conditions based on their bulk and surface-level properties. The research presented in this manuscript was designed to support the fundamental understanding of powder systems by joining experimental and theoretical calculations of dimensionless numbers groups for design purposes. In order to do so, this work focused on two critical variables to better understand fluidization design: physical and chemical surface properties. To better resolve the influence of surface properties, surface-treated powders were used. Five different powder samples of varying particle size distribution were characterized using physical property measurements, including pressure drop profiles to obtain the minimum fluidization velocity, density measurements, and particle sizing. Using theoretical equations, the minimum fluidization velocity was also calculated to compare with those obtained experimentally and determine typical dimensionless number groups used in bulk handling system design. The results showed that the theoretically determined values were lower than those calculated using the experimentally umf. In the case of the Reynolds number, the experimental values were 3–20% higher than the theoretical values, which is an important distinction for designing conveying systems and pipeline flow. Similar results were observed for the theoretical and experimental Froude numbers, indicating an important dependence on the cohesive properties of the particle interactions. Additional dimensionless number groups were considered, including the granular bond number and flow factors. To investigate the influence of surface forces, Hamaker constants were utilized for alumina and polydimethylsiloxane in the calculation of the granular bond number. A lower granular bond was observed with a decrease in the Hamaker constant for PDMS, suggesting that the surface forces would be lower for our surface-treated powders.","PeriodicalId":507225,"journal":{"name":"Powders","volume":"61 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139181850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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